Doctor will not perform surgery

[Vince Carter]

If two guys on TRT are identical except for SHBG, then the same testosterone dose will yield the same free testosterone in each.

You live in your head too much with studies; "identical" guys...come on. SHBG of 20, and SHBG of 70 same dose = same Free T...this isn't the PeakT forum you're on now. I know this nonsense reigns over there but even you can't believe this goofy logic you're trying to sell.

 

[Systemlord]

The individual rate at which men metabolize/secrete T would make for varying Free T levels between men, SHBG is not the only factor.

 

[sh1973]

Yeah got to agree with Vince here, this certainly is not typical. For instance my shbg hovers near 70 and someone with shbg at 24 with both of us taking 100mg per week will certainly have a massive difference in the amount of free t. Man I'm at basically a 1000ng day 7 after a 100mg dose and someone with low shbg would only be at 300-400ng on day 7.

 

[sh1973]

Even if you use the new tru t measurement with those numbers its a massive difference.

 

[DragonBits]

You live in your head too much with studies; "identical" guys...come on. SHBG of 20, and SHBG of 70 same dose = same Free T...this isn't the PeakT forum you're on now. I know this nonsense reigns over there but even you can't believe this goofy logic you're trying to sell.

It wasn't that far off.

My shbg shot up form 40 > 70, my free T stayed at about 1.4-1.7% of total T regardless of my shbg.

However, my E2 changed from 3-4.14% of total T when my shbg was around 40 to 1.98-2.5% when my shbg was 70.

I don't know it was the rise in shbg that dropped E2 percentage of total T, the supplements i took that likely caused shbg to rise may have caused E2 percentage to drop by a different and independent means.

Another thing I am unsure about, estradiol is created from testosterone, but is it from total T or whatever free T is left after binding to shbg?

When testosterone is cleaved from the ester it is attached to, I can't believe that testosterone is immediately bound to shbg, there must be a lag time between when testosterone is in the blood stream and when it gets bound to shbg. So I am guessing there must for however short a time be a big rise in free T, if only locally near the injection site.

IMO when you try and get down to the nitty gritty details, it's all a little complicated.

I tend to only pay attention to total T, some attention to E2 and only if it's over 50 or under 20, getting a free T measure is interesting but what should I do about it?

I did virtual no blood tests for 5 years on TRT when I self directed, the last few years I did a lot of blood tests, way more than needed, now I am returning to the feeling I don't really need to get blood tests once I am dialed in, but I do only do it now because doctors want it.

The theory is interesting, but it's not like I am a clinician needing to treat a lot of different men that may react in different ways, I only need to concern myself about how i react, and I have a pretty good idea now.

 

[Cataceous]

The individual rate at which men metabolize/secrete T would make for varying Free T levels between men, SHBG is not the only factor.

Agreed there are other factors, but if Vince is going to make generalizations about high versus low SHBG then we have to agree to fix the other variables, unless you can demonstrate they are linked to SHBG. My statement is meant to apply when metabolic clearances are the same except for the influence of differing levels of free testosterone, which are caused by differing levels of SHBG.

 

[Cataceous]

Yeah got to agree with Vince here, this certainly is not typical. For instance my shbg hovers near 70 and someone with shbg at 24 with both of us taking 100mg per week will certainly have a massive difference in the amount of free t. Man I'm at basically a 1000ng day 7 after a 100mg dose and someone with low shbg would only be at 300-400ng on day 7.

Ok, here's the first claim: two guys chosen at random on TRT with the same doses: Relative SHBG levels between the guys will not be predictive of relative free testosterone. The relevant variables are independent of SHBG. These variables are the rate of absorption of the testosterone ester from the injected depots and the components of the metabolic clearance rate that are independent of free testosterone.

The second claim: on average, the guys with higher SHBG will have higher total testosterone, but free testosterone will end up the same.

 

[Cataceous]

You live in your head too much with studies; "identical" guys...come on. SHBG of 20, and SHBG of 70 same dose = same Free T...this isn't the PeakT forum you're on now. I know this nonsense reigns over there but even you can't believe this goofy logic you're trying to sell.

I'm still waiting for the first substantive argument from you on this subject. Useful peer review requires more than a knee-jerk negative reaction.

 

[Cataceous]

...
Another thing I am unsure about, estradiol is created from testosterone, but is it from total T or whatever free T is left after binding to shbg?
...

I am pretty sure that the interaction between testosterone and aromatase occurs only when the testosterone is free. But don't think of SHBG as a permanent jail. It's a reservoir that releases testosterone when free levels drop.

...
When testosterone is cleaved from the ester it is attached to, I can't believe that testosterone is immediately bound to shbg, there must be a lag time between when testosterone is in the blood stream and when it gets bound to shbg. So I am guessing there must for however short a time be a big rise in free T, if only locally near the injection site.
...

It's plausible that there would be focal high-T spots at the injection sites. But in general the cleaving of testosterone from the ester occurs in the bloodstream. It's a slow and steady process, unless you happened to do an IV injection. Otherwise the absorption rate from the injected depots is driving everything (free T, etc.), and this is much slower than other processes.

...
I tend to only pay attention to total T, some attention to E2 and only if it's over 50 or under 20, getting a free T measure is interesting but what should I do about it?
...

As long as it's accurate, free T is more important than total. For those whose SHBG doesn't change much then total can have similar utility. Getting accurate free T is a matter of either paying for an equilibrium dialysis test or using the Tru-T calculator to get a good estimate from total T and SHBG.

 

[Joe Sixpack]

Ok, here's the first claim: two guys chosen at random on TRT with the same doses: Relative SHBG levels between the guys will not be predictive of relative free testosterone. The relevant variables are independent of SHBG. These variables are the rate of absorption of the testosterone ester from the injected depots and the components of the metabolic clearance rate that are independent of free testosterone.

The second claim: on average, the guys with higher SHBG will have higher total testosterone, but free testosterone will end up the same.

Wait what? This is new to me. From what I always understood, a higher SHBG results in lower free T, because higher SHBG binds up more of the T, so you get lower free T. Conversely, lower SHBG will bind up less of the T, leaving the patient with higher free T. And you are saying that this is not true?

 

[Cataceous]

Wait what? This is new to me. From what I always understood, a higher SHBG results in lower free T, because higher SHBG binds up more of the T, so you get lower free T. Conversely, lower SHBG will bind up less of the T, leaving the patient with higher free T. And you are saying that this is not true?

This is true. It applies when you are considering a fixed total serum testosterone; free testosterone has an inverse relationship with SHBG.

The different way of thinking about things is this: the absorption rate of the testosterone we inject is controlling our free testosterone pretty directly, while total T goes where it's supposed to according to our free T and SHBG.

 

[Joe Sixpack]

This is true. It applies when you are considering a fixed total serum testosterone; free testosterone has an inverse relationship with SHBG.

Gotcha. But isn't what you said earlier saying something different? "" Ok, here's the first claim: two guys chosen at random on TRT with the same doses: Relative SHBG levels between the guys will not be predictive of relative free testosterone. ""

 

[Cataceous]

Gotcha. But isn't what you said earlier saying something different? "" Ok, here's the first claim: two guys chosen at random on TRT with the same doses: Relative SHBG levels between the guys will not be predictive of relative free testosterone. ""

The statements are consistent. If you choose guys who have the same total testosterone then SHBG does predict free testosterone. But that is quite different from choosing guys at random. Mathematically, SHBG and free T are the independent random variables, while total T is dependent. We're used to thinking of total testosterone as the driver, but my argument is that it's more appropriate to say that free testosterone is in control. In TRT our injections set free T. And in a normal HPTA, regulation is based on free T, not total T.

 

[Joe Sixpack]

The statements are consistent. If you choose guys who have the same total testosterone then SHBG does predict free testosterone. But that is quite different from choosing guys at random. Mathematically, SHBG and free T are the independent random variables, while total T is dependent. We're used to thinking of total testosterone as the driver, but my argument is that it's more appropriate to say that free testosterone is in control. In TRT our injections set free T. And in a normal HPTA, regulation is based on free T, not total T.

I'm following you now. Thanks for elaborating for me.